Polymer chemistry has reached an advanced state, with many different types of polymers being produced in vast quantities for a wide variety of purposes. Many polymers comprise high molecular weight compounds formed by linking similar or dissimilar monomers together by an addition reaction. Polymers vary in physical characteristics, depending upon their nature and the extent of their polymerization. So-called fully polymerized polymers usually are substantially devoid of reactive sites for further polymerization and in any event are "normally non-reactive," that is, cannot be further polymerized or modified by conventional means.
Although the wide variety of currently available polymers affords a substantial selection regarding physical characteristics, nevertheless many potential applications await the development of polymers having the required characteristics. Therefore so-called "tailoring" of polymers by special, sometimes expensive, techniques during basic polymerization to build in new characteristics has not produced a sufficiently high number of new types and/or characteristics to suit current needs. Accordingly, it would be highly desirable to provide a simple, inexpensive method of providing new polymers and/or modifying existing polymers so as to enhance selected physical characteristics thereof.
The present invention is substantially as set forth in the Abstract above. In this regard, a simple, inexpensive and rapid method is provided for modifying normally non-reactive polymers, changing their characteristics and producing new polymer products. The method comprises contacting a selected fully polymerized polymer containing carboxylic groups, with a catalyst comprising a carbonyl of a group VIII transition element, preferably iron carbonyl, cobalt carbonyl, nickel carbonyl or a mixture thereof. The contacting is carried out in an inert atmosphere, such as nitrogen, until the desired modification is obtained. The resulting product is then recovered from the contacting zone and the catalyst can also be separately recovered for reuse.
Modified polymer products so produced exhibit such changed characteristics over the unmodified polymers as increased viscosity in solution, increased glass transition temperatures, gel-like states at greatly elevated temperatures, increased molecular weight, increased hardness and modified electrical and other properties. These products represent a substantial departure from conventional polymers and demonstrate the practicality of the present method.
Further features of the present invention will be apparent from the following detailed description.